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The prevalence of spinal disc herniations in people with no spinal symptoms have been reported to increase with age; from about 20% in those below 40 years to about 30% in those above 40 years. Spinal disc herniations are usually associated with degenerative changes. Though rare, spinal disc herniations can also be caused by trauma. With an increasing number of older people on U.S. roads with a concomitant increase in the probability of getting injured in a vehicle collision, it is reasonable to expect that some of these occupants can present with clinical findings of spinal disc herniations after a side impact, and attribute these findings to the impact. In this study, we looked at the relationship between real world side impacts and the occurrence of spinal injuries, in particular disc herniations, in occupants involved in such impacts.

Disc herniations in the spine are commonly associated with degenerative changes, and the prevalence increases with age. Though rare, spinal disc herniations can also be caused by trauma. With increasing number of older drivers on U.S. roads, there is an expected proportionate increase in clinical findings of disc herniations in occupants involved in vehicle impacts. Our goal in this study is to determine whether there is a causal relationship between frontal impacts and the occurrence of disc herniations in the occupants of these impacts. We further aim to determine the prevalence of different types of spinal injury and to evaluate the effects of crash severity and other parameters on different types of spinal injury in such impacts. Using data from the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) database from 1993 through 2014, we examined the reported occurrence of all spine injuries for adult occupants in frontal impact.

Disc herniations in the spine are commonly associated with degenerative changes, and the prevalence increases with increasing age. With increasing number of older people on U.S. roads, we can expect an increase in clinical findings of disc herniations in occupants involved in rear impacts. Whether these findings suggest a causal relationship is the subject of this study. We examined the reported occurrence of all spine injuries in the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) database from 1993 to 2014. There were over 4,000 occupants that fit the inclusion criteria. The findings in this study showed that, in the weighted data of 2.9 million occupants, the most common spine injury is an acute muscle strain of the neck, followed by strain of the low back. The delta-V of a rear impact is a reliable indicator of the rate of acute cervical strain in occupants exposed to such impacts.

Approximately 600,000 fatalities occur each year as a result of pedestrians being impacted by motor vehicles (World Bank, 2008). Previous studies (Heller et al., 2009) have utilized databases such as the National Inpatient Sample (NIS) to gain a more thorough understanding of the common injury patterns that occur in real-world traffic collisions involving pedestrians in the United States. The NIS contains records on five to eight million hospital stays annually and provides a wealth of information regarding injuries to hospitalized pedestrian casualties in the U.S. Because of the large number of applicable records in the NIS and the randomized sampling procedure, the data can be used to complete analyses that are not possible with smaller databases such as the Pedestrian Crash Data Study (PCDS), which is not intended to be statistically representative of pedestrian crashes in general.

Over half of the 1.2 million annual traffic fatalities worldwide are pedestrians struck by motor vehicles [ 1 ]. Medical databases, such as the National Inpatient Sample (NIS), have been utilized to ascertain injury patterns in the general population of injured pedestrians [ 2 - 3 ]. However, the authors are not aware of any studies investigating how factors, such as physical impairments, intoxication, and pre-existing medical implants (e.g. hip replacement, artificial knee, etc.) affect the prevalence of pedestrian accidents or injury outcomes. Five to eight million inpatient hospitalization records are included in the NIS annually, and this large sample size allows for analyses that are not possible with smaller data sets on pedestrian injuries. The current study utilizes the NIS to evaluate how several factors such as blindness, deafness, intoxication, and pre-existing medical implants affect injury patterns when compared to the general population of hospitalized pedestrians.

Previous studies have suggested injury assessment reference values (IARVs) for lower neck injury based on scaled upper neck values. This study developed independent flexion and extension IARVs for the lower neck by matching Anthropomorphic Test Device (ATD) data to impact-tested post-mortem human subjects (PMHSs) with mid- to low-cervical spine injuries. Pendulum and sled tests with Hybrid III midsize male and small female ATDs were run under conditions mimicking those of published PMHS torso drop-sled tests and other PMHS studies. Measurements included upper and lower neck forces and moments, head acceleration, head rotation rate, and head/neck angles for the pendulum tests. Rear impacts corresponding to rigid seatback tests without a head restraint produced lower neck extension moments that increased dramatically with test severity, as measured by increasing delta-V and/or decreasing pulse duration.

Each year, over half of the world's 1.17 million fatalities resulting from traffic collisions are pedestrians (World Bank, 2008). Mitigation of such fatalities and serious injuries requires a thorough understanding of the common injury mechanisms that occur in pedestrian impacts. Studying the frequency of injury to each body region and how injury patterns are related may provide additional insight into pedestrian injury mechanisms, which could be used to develop additional prevention strategies. There is a wealth of information regarding pedestrian collisions within national databases that have not been extensively used to investigate these issues to date. This paper presents a review of selected databases that contain information regarding injuries to pedestrians who have been involved in a motor vehicle collision, including the strengths and weaknesses of each in performing this type of analysis.

Pedestrian impact protection has been a growing area of research over the past twenty or more years. The results from many studies have shown the importance of providing protection to vulnerable road users as a means of reducing roadway fatalities. Most of this research has focused on the vehicle fleet as a whole in datasets that are dominated by passenger cars (cars). Historically, the influence of vehicle body type on injury distribution patterns for pedestrians has not been a primary research focus. In this study we used the Pedestrian Crash Data Study (PCDS) database of detailed pedestrian crash investigations to identify how injury patterns differ for pedestrians struck by light trucks, vans, and sport utility vehicles (LTVs) from those struck by cars. AIS 2+ and 3+ injuries for each segment of vehicles were mapped back to both the body region of the pedestrian injured and the vehicle source linked to that injury in the PCDS database.

The complexity of vehicle-pedestrian collisions necessitates extensive validation of pedestrian computational models. While body components can be individually simulated, overall validation of human pedestrian models requires full-scale testing with post mortem human surrogates (PMHS). This paper presents the development of a full-scale pedestrian impact test plan and experimental design that will be used to perform PMHS tests to validate human pedestrian models. The test plan and experimental design is developed based on the analysis of a combination of literature review, multi-body modeling, and epidemiologic studies. The proposed system has proven effective in testing an anthropometrically correct rescue dummy in multiple instances. The success of these tests suggests the potential for success in a full-scale pedestrian impact test using a PMHS.

The structural properties of the four major human knee ligaments were investigated at different loading rates. Bone-ligament-bone specimens of the medial and lateral collateral ligaments and the anterior and posterior cruciate ligaments, obtained from post-mortem human donors, were tested in knee distraction loading in displacement control. All ligaments were tested in the anatomical position corresponding to a fully extended knee. The rate dependence of the structural response of the knee ligaments was investigated by applying loading-unloading cycles at a range of distraction rates. Ramps to failure were applied at knee distraction rates of 0.016 mm/s, 1.6 mm/s, or 1,600 mm/s. Averages and corridors were constructed for the force response and the failure point of the different ligaments and loading rates. The structural response of the knee ligaments was found to depend on the deformation rate, being both stiffer and more linear at high loading rates.

Pediatric pedestrians are frequently involved in Pedestrian versus Motor Vehicle Collisions (PMVCs). While in recent years, the automotive industry has worked towards making cars less aggressive to pedestrians, the efforts have mainly focused on adult pedestrian safety. When they have included considerations for children, only head injuries have been evaluated. The development of automotive counter-measures that provide protection for both adult and pediatric pedestrians requires access to injury criteria for the entire body that specifically account for both the age-dependent tissue properties and the pedestrian's size. The objective of the present study is to derive lateral injury criteria for the head, neck, thorax, abdomen and pelvis that can be used in finite element and multi-body simulations of PMVCs involving the 6-year-old pedestrian (corresponding injury criteria for the upper and lower extremities are derived in part II of this study).